Co-molding display with body of mobile device

ABSTRACT

Tooling and methods for co-molding a body with two different materials. An internal die assembly comprising at least two parts allows for placement of a component and co-molding of the body around the component and then removal of the internal die assembly without disturbing the body.

BACKGROUND

The application relates to methods and tooling for making bodies formobile devices and the resulting body for a mobile device.

Bodies for mobile devices usually include multiple materials. Forexample, glass or other transparent material is often used for thedisplay while the majority of the remainder of the body is often moldedplastic or another molded material. The molding can be accomplished byinjection molding. Traditionally, the display portion of the device isassembled to the rest of the molded body during the assembly process.The later addition of the display portion and other components to themolded portion of the body requires gaskets and the like to mate thedisplay portion to the other components. In addition to beingaesthetically unappealing, the gaskets and having multiple seams wherethe various materials meet the gasket may undesirably capture dust anddirt, which, over time, works to loosen the seal between the variousportions of the body. Moisture has more entry routes into the device,leading to corrosion of internal components. Each of the multiple seamsare also a weak portion in the body where the body is most likely tobreak when dropped.

SUMMARY

Tooling and methods for co-molding a body of a device that comprisesmore than one material are described. The tooling comprises an externaldie assembly and an internal die assembly for forming an exterior and aninterior of the body of the device. The internal die assembly is furtherconfigured for placement of a component of the device that is exposed tothe exterior, such as a display screen. The apparatus holds the bodycomponent of the first material in place while the remainder of the bodyis applied around that component.

The internal die assembly comprises a top and a bottom internal die. Thebottom internal die comprises a top side and a bottom side opposite thetop side, wherein the top side is sloped at an angle relative to thebottom side and wherein the top side comprises a notch. The top internaldie comprises a top side comprising an depression having a shape of acomponent of the body, the depression having a depth. The top internaldie further comprises a bottom side opposite the top side, wherein thesecond bottom side is sloped at the same angle relative to the secondtop side as the top side relative to the bottom side of the bottominternal die. The second bottom side also comprises a notch.

In a method for forming the body of the device, a first component of thebody is placed in the depression on the top internal die. In oneembodiment, this first component is a piece of glass or acrylic used fora display of the device. The device's body is then molded around thefirst component, e.g., by injection molding. In one embodiment, the bodyof the device is formed from a material that is different from the firstmaterial, such as a plastic. The finished body with first component isopen on all but one side and the open side is a narrow opening.

After forming the body with first component, the internal die assemblyis removed by first withdrawing the bottom internal die through thenarrow opening. As the bottom internal die is withdrawn, the topinternal die drops at least the distance of the depth of the depressionso that the top internal die clears the first component that had beenplaced in the depression and the top internal die can be withdrawn fromthe finished body.

The finished body comprises at least two materials, the first componentand the molded body of the device. Since the first component has beenco-molded with the body, the two materials are in direct contact witheach other resulting in a better integration of the two materials into asingle body. In one embodiment, the finished body with first componentcomprises a housing for a mobile device, wherein the first component isa display for the mobile device. The display may be glass and the body aplastic, where the glass display and the plastic body are co-molded.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an apparatus for molding a body of a mobile deviceaccording to one embodiment.

FIG. 2 illustrates placement of a display on an apparatus for molding abody of a mobile device according to one embodiment.

FIG. 3 illustrates the finished body after injection molding the bodyfor a mobile device around the display according to one embodiment.

FIGS. 4A-4B illustrate the removal of the apparatus from the completedbody according to one embodiment.

FIGS. 5A-5B illustrate a cross-section view of the removal of theapparatus from the completed body according to one embodiment.

FIGS. 6A-6B illustrate the bottom internal die of the apparatusaccording to one embodiment.

FIG. 7 is a cross section of the device illustrating installation ofadditional layers for a touch screen according to one embodiment.

FIG. 8 is a more detailed view of embodiment portion of FIG. 7.

FIGS. 9-12 illustrate the assembly of a mobile device according to oneembodiment.

The figures depict various embodiments of the present invention forpurposes of illustration only. One skilled in the art will readilyrecognize from the following discussion that alternative embodiments ofthe structures and methods illustrated herein may be employed withoutdeparting from the principles of the invention described herein.

DETAILED DESCRIPTION

Disclosed is a method for fabricating a body for a mobile device,including the display portion, by injection molding the non-displayportion around the display. The formed body is substantially closed onall but the bottom narrow opening of the body and operates like a sleeveor glove into which the internal components of the mobile device areinserted. The tooling for molding the body comprises external andinternal die assemblies. The internal die assembly comprises two piecesthat together allow for correct placement of the display portion of thebody and then formation of the interior of the mobile body. The internaldie assembly is then removed from the formed body without disturbing theformed body.

Forming the mobile body is described in greater detail with reference toFIG. 1. The internal die assembly 103 comprises a top internal die 105and a bottom internal die 107. The materials for internal die assembly103 are any materials suitable for use with injection molding. Examplesinclude, but are not limited to, steel, a beryllium-copper alloy, andaluminum. The top internal die has a depression 109 in which the display111 fits. The display 111 can be any display used for mobile devices.They are typically glass, polycarbonate or acrylic. Glass provides apreferred user experience with the finished device. Mobile devices oftenhave touch screens and thus the display 111 is then a part of the touchscreen.

The depression 109 holds the display 111 while the body is molded aroundthe display 111. The depression 109 can be any size needed and willdepend on the size of the display 111 needed for the mobile device. Thedepression 109 holds the display 111 well enough that the display 111ends up correctly placed in the finished body but loosely enough thatthe top internal die 105 can be removed from the finished body withoutdisturbing the finished body. The bottom internal die 107 ensures thatthe finished molded body with display 111, has the correct size andshape to fit the inner workings of the mobile device. The internal dieassembly 103 is used with a external die assembly 115 that comprises atop external die 119 and a bottom external die 117. The materials formaking external die assembly 115 are materials suitable for use withinjection molding. Examples include, but are not limited to, steel, aberyllium-copper alloy, and aluminum. Details of the mold, such as forexample, injection nozzles for the material of the non-display portionof the body, cooling holes, insulating plates, and the like are notshown in the drawings, since they can be made in the convention mannerand are not important for understanding the disclosed invention.

The operation of the internal die assembly 103 is described in referenceto FIGS. 2-6. As shown in FIG. 2, the display 111 is placed in thedepression 109 on the top internal die 105. The top internal die 105 isin place on top of the bottom internal die 107.

The remainder of the body is then injected around the internal dieassembly 103 and display 111. The body 313 after molding is a sleeveinto which the internal components of the device can be inserted. Theremainder of the body comprises a second material which can be anymaterial suitable for injection molding. Example materials used forinjection molding include, but are not limited to glass-filled nylon,polycarbonate and various grades of polycarbonate-acrylonitrilebutadiene styrene. In one embodiment, the body 313 is substantiallyclosed on all but one side after formation. The closed portionsoptionally include openings for various ports and components such as acamera lens, an earphone jack, buttons and the like. In someembodiments, the top internal die 105 and/or the bottom internal die 107includes protrusions or shapes result in various grooves or protrusionson the finished body 313. The embodiment shown in FIG. 3 illustrates onesuch protrusion 315 that results in an open groove in the completed body313.

Next, the internal die assembly 103 is removed from inside the body 313.This is made possible by having the internal die assembly comprise atleast two parts. The removal is described in reference to FIGS. 4-5.FIGS. 4A-4B shows the general procedure. The bottom internal die 107 isslid out of the body 313. The removal of the bottom internal die 107allows the top internal die 105 to drop free from the display 111. Asshown in FIG. 4B, the top internal die 105 is then removed withoutdisturbing the display 111 which is now a part of the body 313.

FIG. 5A is a cross-section view of the apparatus in the mold aftercompletion of the body 313. The bottom surface of the top internal die105 and the top surface of the bottom internal die 107, which meet atinterface 535, are angled. When ends 527 and 531 of the top internal die105 and bottom internal die 107, respectively, are substantially flushwith each other, the internal die assembly 103 has the size and shape ofthe internal cavity of the completed body 313. The top surface of thebottom internal die 107 is angled such that end 531 is shorter than end533. The bottom surface of the top internal die 105 is angled such thatend 529 is shorter than end 527. This configuration allows for topinternal die 105 to lower away from display 111 in the body 313 asbottom internal die 107 is slid out of body 313 at the end of body 313corresponding to ends 529 and 533. Additionally, top internal die 105has a notch 521 and the bottom internal die 107 has a notch 523. Thedistance 535 is the distance the bottom internal die 107 can beretracted until notch 523 engages notch 521. FIG. 5B illustrates thatwhen the bottom internal die 107 is retracted sufficiently that notch523 engages notch 521 top internal die 105 has lowered leaving gap 537.Gap 537 is at least as tall as the depth of depression 109 and thus thetop internal die 105 can be retracted without disturbing the display111. Notch 523 engaging notch 521 results in the top internal die 105being pulled out of the body 313 along with bottom internal die 107. Inone embodiment, the bottom internal die 107 is withdrawn about 40 mmwhen notch 523 engages notch 521. At this point, gap 537 is about 0.075mm. The angle of the top surface of the bottom internal die 107 and thebottom surface of the top internal die 105 are determined geometricallybased on the position and depth of the depression 109 in the topinternal die 105. Any number of different size displays 111 for bodies313 for mobile devices can be accommodated by adapting the sizes of thetop internal die 105 and bottom internal die 107 as well as the anglesof the bottom surface of the top internal die 105 and the top surface ofthe bottom internal die 107.

FIGS. 6A-6B illustrate the bottom internal die 107 according to oneembodiment. The bottom internal die 107 includes a channel 641 withopenings 639 through which coolant is guided. This allows for more rapidcooling of the body 313 after molding has been injected. In oneembodiment, the channel 641 has diameter of about 4 mm. The diameter canbe any diameter that fits inside the bottom internal die 107. Thechannel need not have a uniform diameter. FIG. 6A illustrates thecooling channel 641 with a side cross-section. The hatching illustratesthe solid portion of the side cross-section. FIG. 6B illustrates a topcross-section. In FIG. 6B the channel 641 is shown as having a V shapefrom opening 639 to opening 639. Alternatively, the channel 641 can haveany other shape. For example, a U shape would result in a larger surfacearea of the channel 641 inside the bottom internal die 107. An M orspiral shape would result in an even larger surface area. Depending onthe material being used for injection molding the body 313, more rapidcooling (facilitated by greater surface area of the channel 641) isbeneficial.

In one embodiment, the display 111 is the outer layer of a touch screen.The remaining layers of the touch screen are installed after formationof the body 313. Certain materials used in some touch screens, such asindium tin oxide (ITO), may be incompatible the molding process and thuscannot be included when the body is molded around the display 111.Because the body 313 is substantially enclosed on all but the sidecorresponding to internal die assembly 103 ends 529 and 533, touchscreen components 759 are installed by use of remotely operated devicessuch as a robotic arm. FIG. 7 illustrates a cross-section of body 313after insertion of the additional touch screen components 759. FIG. 8illustrates a zoomed in view of the cross-section of body 313 afterinsertion of the touch screen components 759. There is a distance of0.20 mm between the display 111 and the touch screen components 759. Inthat distance is a bonding material. Any suitable bonding materials forbonding components of a touch screen together may be used. The touchscreen components 759 are 0.40 mm thick. In this embodiment, the display111 has a notch 861 which extends 0.50 mm from the top edge of thedisplay 111. The touch screen components 759 layer extends an additional1.00 mm beyond the edge of notch 861. Other configurations are possibledepending on the type of touch screen, size of display 111 andproportion of display 111 to the remainder of the body 313.

The described method using the internal die assembly 103 for forming theinternal shape of the body 313 has the advantage of avoiding fusiblecore injection molding which requires forming a core which is melted outof the finished body when completed. The heating of the body to removethe core limits the types of materials that can be used for the body.Internal die assembly 103 can easily be reused for the formationadditional bodies 313.

FIGS. 9-11 illustrate the assembly of a mobile device using a body 313.FIG. 9 illustrates assembly of the internal body 953 of the mobiledevice to be inserted into the body 313. The internal components 949 areplaced in the bottom portion 947 of the internal body 953. The makeup ofthe internal components 949 differ depending on the type of mobiledevice. The internal components include electronics that provide theoperation intended for the mobile device, for example for a telephone,personal digital assistant and the like. The top portion 943 is placedon top of bottom portion 947. The top portion 943 and bottom portion 947snap together to stay closed. Additionally or alternatively, the topportion 943 and bottom portion 947 are glued together.

FIG. 10 illustrates the internal body 953 inserting into body 313.Internal body 953 had added to it an additional cosmetic piece 1065 thatfits into the groove created by protrusion 315. FIG. 11 illustrates theinternal body 953 inserted into the body 313 and final attachment usingplate 1155 and screws 1157.

FIG. 12 illustrates a body 313 formed according to the methods and usingthe internal die assembly 103 described herein according to a secondembodiment. The display 111 in this body 313 extends to the ends of thebody 313 rather than the body forming a frame around the display 111 inthe same plane as the display 111 as in the prior examples.

Embodiments of the invention have been described herein in the contextof displays for bodies for mobile devices. However, it will beappreciated that certain of the techniques and devices described may beused to achieve the same benefits in the manufacture of other devicesthat incorporate different materials in the housing for the device.Additionally, the same techniques can be used to incorporate othermaterials into the body for a mobile device, such as the microphone andspeaker components of the telephone functionality of the mobile deviceand lens and flash components of the camera functionality of the mobiledevice. Although the dimensions of the apparatus have been chosen inorder to provide optimal use for displays for mobile devices, thefundamental apparatus design can be modified to be used for otherdevices and other components on mobile devices.

The foregoing description of the embodiments of the invention has beenpresented for the purpose of illustration; it is not intended to beexhaustive or to limit the invention to the precise forms disclosed.Persons skilled in the relevant art can appreciate that manymodifications and variations are possible in light of the abovedisclosure. The language used in the specification has been principallyselected for readability and instructional purposes, and it may not havebeen selected to delineate or circumscribe the inventive subject matter.It is therefore intended that the scope of the invention be limited notby this detailed description, but rather by any claims that issue on anapplication based hereon. Accordingly, the disclosure of the embodimentsof the invention is intended to be illustrative, but not limiting, ofthe scope of the invention, which is set forth in the following claims.

The invention claimed is:
 1. An apparatus comprising: a bottom externaldie plate shaped to form a portion of an exterior of a body of a mobiledevice; a top external die plate shaped to form another portion of theexterior of the body of a mobile device; a bottom internal diecomprising a top side and a bottom side opposite the top side, whereinthe top side is sloped at an angle relative to the bottom side andwherein the top side comprises a notch; a top internal die comprising: atop side comprising an indentation having a shape of a display of themobile device, the indentation having a depth at least as deep as athickness of the display and configured to hold the display duringmolding, and a bottom side opposite the top side, wherein the bottomside is sloped at the angle relative to the top side and wherein thebottom side comprises a notch; wherein the top internal die and thebottom internal die come together at an interface between the top sideof the bottom internal die and the bottom side of the top internal die,wherein the notch of the bottom internal die and the notch of the topinternal die are separated by a first distance; and wherein the angleand the first distance are selected so that when the bottom internal dieis withdrawn from the body, the top internal die moves a second distanceequal or greater than the depth when the notch of the bottom internaldie engages the notch of the top internal die.
 2. The apparatus of claim1 wherein the bottom internal die comprises a channel having a first anda second opening on a first side perpendicular to the bottom side of thebottom internal die.
 3. An apparatus for molding a body for a mobiledevice comprising: a bottom component comprising a top side and a bottomside opposite the top side wherein the top side is sloped at an anglerelative to the bottom side and wherein the top side comprises a notch;a top component comprising: a second top side comprising an indentationhaving a shape of a display of the body, the indentation having a depthat least as deep as a thickness of the display and configured to holdthe display during molding, and a second bottom side opposite the secondtop side wherein the second bottom side is sloped at the angle relativeto the second top side and wherein the second bottom side comprises asecond notch; wherein the top internal and bottom internal componentscome together at an interface between the top side and the second bottomside wherein there is a first distance between the notch and the secondnotch; and wherein the angle and the first distance are such that whenthe bottom internal component is withdrawn from the body after molding,the top internal component drops a second distance equal or greater thanthe depth when the notch engages the second notch.
 4. The apparatus ofclaim 3 wherein the first component comprises a channel having a firstand a second opening on a first side perpendicular to the bottom side.